Automatic contact plug



Dec. 12, 1933. c. A, GQQD 1,939,?59

AUTOMATIC CONTACT PLUG Original Filed Oct. 16. 1929 IN VEN TOR. CHAQLE-JA. $000.

Patented Dec. 12, 1933 PATENT AIOF'FICE 1,939,259 7 AUTOMATIC CONTACTPLUG Charles A. Good, Oakland, Calif.

Application October 16, 1929, Serial No. 399,937

Renewed April 3, 1933 Y 8 Claims.

This invention relates to improvements in contact plugs such as employedto'connect electrical appliances with a source of electricity and in itspresent embodiment provides for automatically locking the plug againstaccidental displacement while at the same time permitting of a quick,willful displacement of the plug when desired.

An object of the invention is to provide a plug ofthe characterdescribed in which the contact members thereof are urged into proper andlocking engagement with associated'contact members by a novel springmeans which insures a positive and reliable contact of said members in aparticularly eflicient manner.

Another object is to provide a plug of the character described in whichthe contact members aremovable into position for alignment andcooperation .with their associated contacts and also movable out oflocking engagement with said contacts by a comparatively simple pushbutton means arranged to be readily operated as desiredto facilitate theinsertion and removal of the plug. 1 Still another objectof theinvention is to provide in a plug'of the character described an improvedform of completely assembled contact unit wherein the means for movablyor pivotally anchoring the contact member in the plug body,

0 the spring actuating means for said contact member, the'interlocking.means at the free endof said contact member, and a push button formoving the contact member, are carried by and entirely supported on thecontact member and form said complete unit, which greatly facilitatesthe assembling .and disassembling and simplifies the construction of theplug.

A further object is to provide a plug of the character, described inwhich the contact memo bers and other parts, although of comparativelysimple and inexpensive form, render the plug safe, durable andanswerable to all requirements of the law and insurance companies. V

The invention possessesother objects and features of advantage, some ofwhich, with the foregoing, will be set forth in' the followingdescription of the preferred form of theinvention which is illustratedin the drawing accompanying and forming part of the specification. It isto be understood, however, that variations in the showing made by thesaid drawing and description may be adopted within the scope of theinvention as set forth in the claims.

Referring to the drawing,

Figure 1 represents a fragmentary top plan view tion.

Figure 3 is an end in Figure 1.

Figure 4 is a fragmentary dotted lines the plug as when inoperativeposielevation of the plug shown 9 side elevation of the contacts showinghow electrical contact is maintained while pulling the contacts apart.

Figure 5 is a perspective view of one of the complete contact units.

Figure 6 is a fragmentary top plan view of a modified form of the plug,wherein the push buttons are omitted.

Figure 7 is a fragmentary side elevation of the type of associatedcontactxto be used with the plug shown in Figure 6.

Figure 8 is a side elevation of a multiple type contact device whichprovides for connection of a plurality of circuits with the plug contactdevice of Figs. 1 and 6; i

The present embodiment of the invention'as shown in detail in theaccompanying drawing 30 comprises a plug body 1 formed of like halves 2and B'held together by suitable fastenings 4 and 'having the usual 1electrical conductors 5 disposed in grooves 6 which are arranged toreceive the strains on the connections of said conductors 35 with thecontacts. 7

Arranged in openings 7 formedby the halves of the plugare two contactunits which are preferably completely assembled inthat all the partsthereoi'are self, contained. As here shown each unit includes anelongated flat resilient metal contact member 8 having at itsinner'endan en-' largedrounded portion 9 carrying a binding post 9, the portionQfitting in asocket 10. in the plug body in such manner asto. provide apivotal 5 anchorage-for the contact member. Thus the lower end of saidmember is free'to bemoved laterallybut the contact is prevented fromlongitudinal displacement. On the outer end of the contact there isprovided an outwardly laterally bent slightly rounded terminal 11 whichwill interlock with the associated contacts 12, each of Whichlatterisprovided. with a long contact surface'13 terminating in an oiiset innerterminal 14 providing a locking shoulder 15.

Spring means is preferably provided for urging the plug contacts'8intoclose and interlocking engagement with the associated contacts andas here shown are carried by the contacts themselves, in the form ofbowed leaf springs 17 secured as at 18 at certain ends to said contacts.The convex portions 19 of said leaf springs slidably contact with theopposed walls 20 of the openings in the plug body, whereas the free endsof the springs likewise engage to opposed faces of the contacts 8.

Preferably carried by the contacts 8 between the endsthereof are pushbuttons 22 which extend outward through lateral openings 23 in. thesides of the plug body, and constitute means for moving the contactsagainst the action of the springsl'l into position to be aligned andlockingly engaged with the contacts 12; also for, moving the contacts 8out of locked engagement with the contacts 12. These push buttons may besecured to the contacts 8 by the fastenings 24 or in any other suitablemanner fixed to said contacts. It will now be clear that the contacts 8with the rounded ends 9, springs 1"], ends 11,

and push buttons 22 comprise completely assembled units which may *bemuchmore easily, accurately, and in less time properly positioned orassembled in 'the'plug than'would be possible where separate parts areemployed.

.With the plugfandiassociated contact shown in Figures 1 and 2, to plugin the plug, the. operator del esss the push buttons 22 and therebymoves the contacts 8 inward so as to align them with the slots 26 in thecontact 12. The contacts 8 are then inserted in the slots 26 and areheld in engagement with the. contact surfaces 13 while beingthusinserted, until the ends 11 interlock with the shoulders 15. Thusengaged, the contacts 8 will be locked against accidental displacementbut whenthe plug. is forciblyfland willfully moved outward the contactwill. release but while being drawn apart will, as shown in Figure 4,remain-in engagement until the ends 11 are moved clear of the slots 26.Thus arcing is minimized and a proper. contact will be insured'althoughthe operator. fails, to pushthe plug as far. inward. asv is required to.interlock the contacts or fails to pullit all theway outs ward.

It will be seen that althou h the shoulders 15 and ends 11 effectivelyinterlock the con:

tacts in such manner that release; may be effected' when the plug isforcibly withdrawn, the release by the push button is. preferable. Whenthe push buttons are, depressed the contacts 8 are moved laterally clearof interlocked engagement with the shoulder 15, thisbeing permitted bythe widthv of the slots 26, but an. electrical contact is maintained 'ashereinbefore stated.

Thus, the release of the plugthrough operation ofthe push buttons maybequickly and conveniently. effected when desired.

As shown in Figure 6 the plug may be constructed without the push buttonrelease. Instead, the contacts 8. are held slightly spaced from thewalls of the opening 27 in the plug by the lugs 28; and said contactsare at all timesin position to be inserted in the slots of or otherwiseengaged with the contacts, one of which is designated 16 and shown inFigure '7. The entrance end of the slot of this contact is flared orenlarged and provides a beveled face 29 which guides the ends of thecontacts 8 into theslots. Otherwise these contacts are the same as thecontacts 12 and cause the contacts 8 to be inter locked againstaccidental'removal therefrom, but will permit of release and withdrawalof the plug contacts when the lug. i QrGibly, willfully withdrawn.

- electrical appliance.

In this connection it is important to note that with plugs of the typesshown in both Figs. 1 and 6, an appreciable safety and good contactfactor is provided, owingto the long contact surfaces 13 of theshoulders 15, the ends 11 and the spring urging the contacts into closeengagement. For example, should the plug be accidentally pulled orvgripped with suflicient force to move the ends 11 of the contacts 8 outof interlocking engagement, but not with sufficient force to entirelywithdraw the contacts 8, the electrical connection will not have beenbroken and will remain effective. With the contact in the position shownin Figure 4, for example, a reliable electrical connection is stillprovided and will be maintained due to the spring means mgmg thecontacts into close engagement with one another.

Another point of advantage is that the inherent resiliency of thecontacts 8 is brought into play when said contacts are in operativeposition and this. with the force of the springs insure a good contactof the parts at all times. 4

As shown, in Figure 8, I may employ a multiple form of associatedcontact device for. the plugs shown in Figs. 1 and.6. This multiplecontact device comprises.- body members 30fof insulation material,carried by a base 31. Each member 30 is provided with a slot 32 forreception of one of the plug contact members 8. At spaced points in theslot are contacts 33 and 34 each having a socket portion 35 for.interlocking engagement with the endsv 11 of the contacts 8. When thecontacts 8 are pushed all the way.v into the slots 32 the ends 11 willengage the contacts 34-and the, contacts 8 will be clear of the contacts33. On pulling the plug. outward slightly the ends 11 of the. contacts 8will'be moved clearv of the contacts 34.and .into engagement: withthecontacts 3.3. contacts. 33 and 34 will interlock withthe ends 11 ofthe contacts 8 in the same manner as provided by the contacts 12. Thusthe multiple contact device shown in Figure 8 will provide for. theindependent connection of a plurality of circuits. For. example, as.shown in Figure 8, A and B. indicate two heating element circuitsincluding heating elements'C andD of different sizes 'or capacitiesQThese two elements may be embodied in an electric iron or in any similarWhen the plug contacts 8 are in engagement with the contacts 34 thelarger elementC is. connected for operation, but on pulling out theyplug. untilthe contacts 8:snap into. engagement. with. the contacts 33,then-the smaller element-D willsbe energized. In this way the heat maybe regulated and controlledwith the simple contact means of thisinvention; butI- wish itunderstood that the multiple contacts maybe putto uses other than here described.

Although the plug-contacts are here shownas contained within the'plugbody, I may arrange said contacts to project outward from the body inthe manner commonly usedin certain types of present dayplug'sfFurthermore, the associated contacts may be of the socket type insteadof. the type here showmit being obvious that the advantages of thisinvention are obtainable with all of said types of plugs and contactdevices, It will now be Cle r that the plug ofmy invention, constructedand arranged as hereinbefore described and as shown in the drawing, willaccomplish the purposes of, the invention in a particularly eflicientmanner.

It will be noted that in bothinstances the I claim:

1. In a contact plug, a body portion and a completely assembled contactunit carried by the body portion and comprising an elongated contactmember, means carried by and at one end of the contact for pivotallyanchoring the contact in said body portion, means at the other end ofand carried by said contact member adapted to interlock with anassociated contact, spring means carried by and between the ends of saidcontact member and arranged to urge the said contact member intoposition to engage said associated contact, and a push button carried bysaid contact member and extending outward of said body portion.

2. In a contact plug, a body portion having an opening therein for acontact unit and a socket contiguous with said opening, and a contactunit in said opening comprising an elongated contact member, meansformed integral with said contact member at the inner end thereof forpivotally socketing the contact in said body portion, means formedintegral with the other end of said contact member adapted to lockinglyengage with another contact, a spring arranged to urge the contactmember at all times in one direction, and a push button fixed on saidcontact member and disposed in accessible position on one side of saidbody portion.

3. In a contact plug or body portion having an opening therein for acontact unit, and a contact unit carried in said opening and comprisingan elongated contact member, means for movably anchoring the contactmember in said opening, a spring fixed to and carried by said contactmember between the ends of and urging the contact member laterally inone direction at all times, and a push button fixed to said contactmember extending outwardly of the casing in position to provide formovement of the contact member against the actions of said spring.

4. In a contact device, plug contact members, and other contact memberseach comprising a slotted member adapted to receive in the slot thereofone of the plug contact members and a plurality of spaced contactelements contained in the slots of said last named contact members andarranged to be selectively engaged by said plug contacts.

5. In a contact device, plug contact members and other contact memberseach comprising a slotted member adapted to receive in the slot thereofone of the plug contact members, a plurality of spaced contact elementscontained in the slots of said last'named contact members and arrangedto be selectively engaged by said plug contacts, and means formedintegrally with the plug contacts and with said elements for causing aninterlocking engagement of the contacts and said elements.

6. In a contact device, a plurality of contact members each having aguide slot associated therewith and a plurality of spaced contactelements in each slot arranged to be selectively and independentlyengaged by a plug contact member when the latter is inserted into orpartly withdrawn from said slot, and laterally yieldable plug contactmembers arranged to be inserted into said slots to selectively andindependently engage said contacts, said plug contact members and saidcontact elements being constructed and arranged whereby disengagementthereof can only be effected upon lateral yielding of said plugcontacts.

7. In a contact device, a support, a plurality of spaced contact membersarranged in a row on support to be selectively and independently engagedby a plug contact member when the latter is moved axially in a pathalongside said spaced contact members, a laterally yieldable plugcontact member arranged to be moved into and out 5 of engagement asaforesaid with said spaced contact members, and cooperatinginterengaging portions on the first and second named contacts arrangedin laterally offset relation to said path the row thereof, and portionson the first and second named contacts being ofiset laterally in thedirection of the spring urged movement of the second named contacts andarranged to releasably interlock with one another.

CHARLES A. GOOD.

